Attachment plug



Dec. 4, 1928.

F. L. AIME ATTACHMENT PLUG Fild Dec. 9. 1921 2 Sheets-Sheet l ,E m A L M MW u w U H0 E a 4 2 Dec. 4, 1928,

F. L. AIME ATTACHMENT PLUG Filed Dec. 9. 1921 2 Sheets-Sheet 2 Patented Dec; 4, 1928.

- UNITED s rA FRANK IQ, AIME, OF SPOKANE, 'wnsrnneron;

ATTACHMENT PLUG.

Application filcdDecember 9, v1921 Serial no; 521,110.

- This invention relates to attachment plugs for electrical accessory apparatus, and more specifically it relates to the internal construction of such plugs; v I

It is an object of this invention toprovide an improved attachment plugof the sectional or divided type which is particularly adapted for heavy duty and "which is positively maintained in nornialposition against jarring and other loosening effects which cause destruction by overheating and shortcircuits. Another object of the invention is to provide a rugged twopartelectrical connecting l5 plug which is capable. of carrying relatively heavy currents and which is susceptible of quick manufacture at materially reduced costs. I i V LA further object of the invention is to provide a simple means forlocking together at will the various parts of the plug; 7

Other object-sot the inventionwill be ape parent from a reading of the following detailed description. T

Heretofore attachment plugs for heavy duty accessoryapparatus, such as hand drills, large heaters and the like, have been destroyed by becoming overheated or short circuiteddue to the looseningof the plugs in the sockets by arring or other vibrations: It is well understood that reduced contactareas require more current to i be transmitted through smaller quantities" of metal and that under suchcircumstances the metal becomes overheated and destroyed. Such heating and de- 1 struction of the conducting metal in attach- I ing plugs and sockets usually results from the loosening of the joined parts of the plug by the constant vibration of the buildings in '40 which the the heavy duty apparatus is employed or the bodies upon which thesockets are mounted. 7

My invention contemplates an attachment plug which may be aflixed in full current conducting relation in a socket and which may be held in such positionagainst vibrations and like loosening causes. 7 In addition I contemplate the production ofheavy' duty attachmentplugs which substantially eliminate fire risks and which maybe positively locked in normal operating position.

A selected embodiment of my invention is illustrated. in theaccompanying drawings wherein.

Fig" i is a sectional view of an; attaeh on the line of 22 of Fig. 1.

g some of the constructional Fig. 1 is a top pl baseportion of the plug.

Figs. 5 and 6 are respectively, plan and elevational views of a shell contact which is incorporated in the base of the plug.

Fig. 7 is a sectional View of a modified plug" showing a spring pressed center contact.

7' is a sectional view of the modified plug shown in Figure 7 andta'ken at-right angles to the section in that figure;

I Fig. Sis a sectional view of: the modified plug showing a different type of 'engaging contact. Q

Fig.9- is also a sectional view of the modified plug taken on the line of 9 9 ofFig. 8.

. Figs. 10 and 11 are respectively a sectional an view of a to those drawings and particu 1,693,972 TESPAT'ENT OFFICE.

elevational and plan views of an insuluating ring, t

larly to Figs/1 to 6, inclusive, the preferred 1 attachment plug is shown as comprising a base 1 adapted to be screwed into an electrical socket and a cap 2 provided with suitable electric contacting membersand adap'tedto be thrust into engagement with base 1 and to be locked thereto when desired.

The base 1 consists of the well known parts such as outside contact 3, insulating bodies i and 5 made ofporcelain or other desirable, I

material, and a central contact 6. The con-' tact 3 as well as conductingcurrent functions to hold together some of the parts of the base The central contact 6 may be incorporated 'in' the baggie any desired mannerwhieh will permitlongitudinal movement thereof with tact?) has its lower end pressed or formed. into respect to the other contact of the base. The preferred manner belng to form screw threads on its lower portion and to have it engage a stationary screw threaded bushing 11. ;The

lower end of the contactfilcarries a metal washer 12 which engagesthe centralcontact ofan electrical socket. This washer also functions to limit the upward movement of. the contact 6. The top portion 13 of the contact receives one of the contacts carried by the cap and is so formed that it may be rotated by rotating the cap. I have found that b forming slots 14 in portion 13 that a suital ile contact of thebayonet type carried-by the cap may be .insertedin one 'ofslots 14 and rotated to move contact 6 relatively to contact3. A suitable insulating bushing 15 surrounds portion 13 and is preferably affixed thereto. By extending the top of this bushing above the top surface of the base, I

thereby provide anotherway for moving the central contact 6 longitudinally, as the bushing may be readily rotated by the thumb and fin er. 1

The capof the plug consists of an insulator 16 of suitable material, one or more bayonet contacts17whichengagewith ring 8 of shell contact 3, and a centralbayonet contact 18 which engageswith contact 6. Thecap may be constructed of-molded material or of pressed metal with proper insulation for the current carrying parts. Contacts 17 have curved portions 19 which engage a bead QO' formed in ring 8 thus providing one means for holding the cap from being snapped out of the base by a slight pull on the connecting cord, Another means for holding the cap in contact with the base is by havingthe curved 7 3. Although I-have illustrated specific forms portions 19 moved into restricted cavities in insulating ring 5 (see'Fig. i The contact-- 18 may be constructedin any desired manner, one form being illustrated in Figs. 2and of engaging means between thecontacts in both the base and cap, I wish to be understood as contemplating any form of engagement which permits positive contact and relative movement. Examples of some of these forms will later be described. 3

' operation.

f Having now described the constructing of the plug, consideration The base 1 .isinserted in a socket the usual manner and screwed into normal position. In order to firmly aflix and maintain the base in the socket, the centralv contact-6 -.into more )ositive contact with the central l is rotated by. rotating bushing 15 by the thumbandfinger thus carrying washer 12 contact oft e socket; this movement forcing A the screw threaded portion of contact 3 into positive LCOIltEtCt' with the threads of the gagementbetweenthe base and the socket socket, thus causing a positive-frictionalenthat is notas susceptibleof being loosenedby will be hadlasto its jarring or by other vibrating movements as the prior type of plugs; Th'lspositlve engagement between the conducting parts of the base and a socket causes the full designed areas of the contacts to positivelyengage each other and thus eliminate overheating which takes place when only a portion ofthe desired conducting surfaces are in contact,

After'the basevhas been firmly affixed in the socket and read for operation the cap '2 may be inserted inthe base so that the bayonet contactlS engages slotted portion 14: of contact 6, and the contacts17 move into positive contact with the'shell contact 3. Inthe event that-the endsof contacts 17 have been bentout of their normal position, they are guided into proper contact with shell 3 by the curved edge 21 of the bushing 15 and by the turned up ends of the contacts. i

After the cap has been thus inserted as illustrated in Fig.1 it maybe rotated to move contact 6 into. positive engagement if the base has not already been locked into po sition, otherwise it is given onlyv a slight rotational movement in order that curved portions 19 of. contacts 17 may be carried into 3. These flanges prevent the contacts 17 from beingdr'awn awa from bead 20, thus locking the cap to the h of the cap is readily accomplished by rotatingthe cap to the right or left until contacts 17 are free to be withdrawn onto the right when the washer 12 has not been tightly screwed to the'center contact of the socket.

Myinvention permits theuse of a plug havringthe minimum amount of conducting metal and it is especially adapted to be employed with electrical accessories which require relatlvely. heavy current for their operation, ah-

though it IS to be. understood that such a plug may be readily employed withother apparatus and may-or may not be locked in po sition dependingupon the;conditions of operationsnl As heretofore mentioned the preferred ase. The unlocking cavities underfianges 22 asillustrated in Fig.

doe

xform of plug may be: modified. ()ne ofthe modified forms is illustrated in Fig.7 wherein there-"is provided a springf23 for movinga lower portion 24of the central contact'into engagement with the central contact of the socket. Such a construction permits the base i to be aflixed in normal 'position'without requiring special manual attention, and itauto- 'maticallymaintains a positive contactlshould the. socket be screwed only part way to its normal position. This'modified-form of plug prevents overheating under substantially anyclrcumstances. 1 Another:modification of my "improved attachment'plug will bedesoribed in connection with Figs. 8 to 13, inclusive. The upper rportion of shellv contact 3 is provided withseparate up-rights 25 which permit the modified bayonet-contacts 26 carried by the cap, to. be.

received between them and the upper portion 27 of the shell. Rotary-movement'is given to the central contact by rotation of the cap and shoulders 28of bayonet contacts 26 are 5, thus carried under lips'29 of insulating rin providing'a means for preventing there moval of the cap.

Particular reference to Fig. 12 illustrates" the bayonets 26 and shoulders 28 which engage the insulating ring 5. The particular construction of this modifiedinsulating ring is shown in Figs. and 11 and illustrates the cut-away portions 30 for the ends of'the contact '3 and shows the lips 29 under which shoulders 28 are moved.

Other modificationsand changes may be made in the construction herein illustrated,

but suchv modificationsand changes are con under which said cap contact may be moved while still maintained in engagement with said base contact to prevent the abnormal withdrawal of said cap without deforming some part of the complete plug.

2. In an electrical attachment plug, the combination of a base and a cap adapted to be assembled therewith, two electrical contacts carried by said base, two electrical contacts carried by said cap and adapted to initially engage said base contacts as said base and said cap are brought together, and'means in said base under which one of said cap contacts may be moved while still maintained in engagement withone of said base contacts to prevent the abnormal withdrawal of said cap without deforming the cap contact positioned under said means.

3. In an attachment plug, a base provided 7 with an electrical contact which has a curved. portion, a cap adapted to be brought into en-' gagement with said plug, an electrical contact carried by said cap, said contact having a curved portion and arranged to engage said curved portion of the base contact to thereby form a means for temporarily holdingfsaid base and said cap in assembled relation, said base being provided with a portion under which the curved portion of the contact car ried by said cap may be moved While being maintained in engagement with the contact carried by said base to prevent the separation of said contacts.

4. In an attachment plug a base provided with separate electrical contacts, a cap adapted to be brought into engagement with said base, separate electrical contacts carried by said cap and arranged to engage the contacts of'theqbase, one of the contacts carried by said cap being curved toengage a curved por tion of one of the contacts of said base to thereby form a temporary locking means between said cap and said base, said base being alsoprovided with a projeetion'under' which said curved contact of said cap may be moved while being maintained in contact with thecurved contact carried by said base, said pro ection acting to prevent the contacts from being separated withoutdetormingthe' curved contact of said cap.

5.. In an attachment plug a base provided 'with two electrical contacts separated by in-' sulating material, a cap adapted to. "be brought into engagement with said base, two separate electrlcal contacts carried by said cap and arranged to engage the contacts in 1 said base, one of the contacts carried by said base being provided with a beaded portion,

one of the contacts carried by said cap being adaptedto engage the beaded contact of said relative movement to said screw threaded contact, a resilient means for biasing said central contact outward, "said two'contacts arranged to engage contacts in an electric light socket when normally positioned therein thereby lorcing said central contactsomewhat back into said base and to thereby cause said screw threaded contactto positively engage the corresponding contact of said socket, the other end of said screw threaded contact being extended to the interior of said base and being provided with a beaded portion, a

cap arrangedto be assembled on said base, contacts carried by said cap to engage said two contacts of said base, one of said cap contacts being beaded toengage the beaded portion of said screw threaded contact' exten- -7. In an attachment plug the combination of a base, two contacts carried therebyand separated by an lnsulating material, one of said contacts'being constructed to be moved longitudinally to the other contact,resilient means for controlling the movement of said tact=witl1sa1d base, and contacts carried by said cap and insulated from-each other and tact carried by said base member and extend ing outwardly therefrom, spring means for moving said contact outwardlyya cap mem-; ber provided with two electrical contacts in- Sula-ted from each otheiyone of said contacts adapted to engage the contacts in said base,

means for tempoifarily locking said contacts in engagement, and means for locking said contacts against separation ithout deform ing one o'f them after they have been moved relatively a predetermined distance while: p

a base and being so positioned as to extendover still being maintained in engagement.

'8; Inan attachment plug the combination of a base member provided With a screw threaded-contact mounted on the outside; thereof and having an extension tothe interior of said membensaid extension being provided with a beaded portion, a central concontacts carried thereby engage the contacts carried by saidbase member so the two beaded contacts engageleach other, said base V momberbeing so constructed asto permit the b cap to be rotated 360 while said contactsare" in engagement, and ashonlder carried bysaid the beaded portionof the extension of said screw threaded contact fora portionof the 7 360 thereby forming a means to prevent the separation o fsaid cap from said base when the beaded contact carried by said .cap is Tunder said shoulder. a v a Signed at Spokane in the county ofSCpokaneiand State of Washington this-3rd of .December A. D. 1921, a

" FRANK L. AIME; 

